CN113419375A

CN113419375A - Optical film, polarizer and display device

Info

Publication number: CN113419375A
Application number: CN202110674246.7A
Authority: CN
Inventors: 徐成义; 王小丽; 龚庸才; 朴炳仁; 舒勇; 曹杰; 陈守年; 张恒; 王楠; 徐学磊; 黄炯; 夏叶荫; 谢王宝
Original assignee: BOE Technology Group Co Ltd; Hefei BOE Optoelectronics Technology Co Ltd
Current assignee: BOE Technology Group Co Ltd; Hefei BOE Optoelectronics Technology Co Ltd
Priority date: 2021-06-17
Filing date: 2021-06-17
Publication date: 2021-09-21
Anticipated expiration: 2041-06-17
Also published as: CN113419375B

Abstract

The application discloses an optical film, a polarizer and a display device, wherein the optical film is arranged on the light-emitting side of a backlight source and is used for at least improving the backlight light-emitting quantity of a viewing angle of 20-60 degrees and/or-20-60 degrees. According to the scheme, the optical film can at least improve the backlight light output quantity of the field angle of 20-60 degrees and/or-20-60 degrees, so that the brightness of the field angle of 20-60 degrees and/or-20-60 degrees can be improved under the condition of not improving the backlight brightness, namely the side-looking brightness is improved, and the development of products towards the direction of low power consumption is facilitated.

Description

Optical film, polarizer and display device

Technical Field

The invention relates to the technical field of display, in particular to an optical film, a polarizer and a display device.

Background

For a currently common LCD (Liquid Crystal Display) Display module, the distribution of Display brightness is similar to an ellipsoid, i.e., the brightness at the front viewing position is the maximum, the brightness at the side viewing position is reduced, and the Display brightness rapidly attenuates with the increase of the side viewing angle.

However, some current display devices are mainly viewed in a side view direction, such as, but not limited to, Touch Bar in some notebook computers, Touch Bar is disposed on top of the keyboard region, which can display Esc keys, dock applications, screen brightness, switch between do-not-disturb modes, turn off the display, display weather, time, battery information, etc., and can complete corresponding operations by touching corresponding icons. Since Touch Bar is arranged on the top of the keyboard region, it is generally viewed by the user from the side according to the position relation between it and the user, i.e. the viewing angle of Touch Bar is about 30-40 ° for the eyes of the user; and rarely by the front view, the direction of perpendicular Touch Bar is watched promptly, therefore this just requires that it has higher luminance on the side direction, at present, in order to make the side direction have higher luminance, only realize through the mode that improves backlight brightness, adopt the consumption that this kind of mode can improve the module, is unfavorable for the product to low-power consumption direction development.

Disclosure of Invention

The application expects to provide an optical film, polaroid and display device for can improve the display brightness who looks sideways at the direction under the circumstances that does not improve backlight brightness, so as to do benefit to the product and develop to the low-power consumption direction.

In a first aspect, the present invention provides an optical film which is provided on a light exit side of a backlight and which increases at least the light exit amount of the backlight at an angle of view of 20 ° to 60 ° and/or-20 ° to-60 °.

As an implementable manner, the optical film includes a substrate layer, and a side of the substrate layer facing the backlight is provided with an optical microstructure for changing a light propagation path to a predetermined direction.

In an implementation manner, the optical microstructures are strip-shaped protrusions with triangular or quadrangular cross sections.

As a realizable way, when the cross section of the optical microstructure is a quadrangle, the quadrangle is a trapezoid.

As an implementation manner, the lower base of the trapezoid is connected to the substrate layer, the upper base is far away from the substrate layer, and the backlight light output amount of the 0 ° field angle is positively correlated to the length of the upper base.

As an achievable way, the heights of at least some of the strip-like projections differ.

As an implementation manner, when the cross sections of two adjacent strip-shaped protrusions are equal, the distance between the vertexes of the two adjacent strip-shaped protrusions is less than or equal to the bottom edge of any one of the two adjacent strip-shaped protrusions; under the condition that the cross sections of two adjacent strip-shaped bulges are similar, the distance between the vertexes of the two adjacent strip-shaped bulges is smaller than or equal to the bottom side with larger size in the two adjacent strip-shaped bulges.

In an implementation manner, the cross-sectional shapes of the optical microstructures disposed on the same substrate layer are similar.

In a second aspect, the present invention provides a polarizer, including the above optical film.

In a third aspect, the present invention provides a display device, including the optical film or the polarizer.

According to the scheme, the optical film can at least improve the backlight light output quantity of the field angle of 20-60 degrees and/or-20-60 degrees, so that the brightness of the field angle of 20-60 degrees and/or-20-60 degrees can be improved under the condition of not improving the backlight brightness, namely the side-looking brightness is improved, and the development of products towards the direction of low power consumption is facilitated.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:

FIG. 1 is a light-guiding optical simulation of an optical film according to a first embodiment of the present disclosure;

FIG. 2 is a diagram illustrating correspondence between optical propagation paths and brightness of viewing angles of an optical film according to a first embodiment of the present disclosure;

FIG. 3 is a light-directing optical simulation of an optical film according to a second embodiment of the present disclosure;

FIG. 4 is a diagram illustrating correspondence between optical propagation paths and brightness of viewing angles of an optical film according to a second embodiment of the present disclosure;

FIG. 5 is a diagram illustrating correspondence between optical propagation paths and brightness of viewing angles of an optical film according to a third embodiment of the present disclosure;

FIG. 6 is a diagram illustrating correspondence between optical propagation paths and brightness of viewing angles of an optical film according to a fourth embodiment of the present disclosure;

FIG. 7 is a schematic structural diagram of an optical film according to a fifth embodiment of the present disclosure;

FIG. 8 is a schematic structural diagram of an optical film according to a sixth embodiment of the present disclosure;

FIG. 9 is a schematic structural diagram of a polarizer according to a seventh embodiment of the present invention;

fig. 10 is a schematic structural diagram of a display device according to an eighth embodiment of the present invention;

fig. 11 is a schematic structural diagram of a display device according to a ninth embodiment of the invention.

Detailed Description

The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

As shown in at least fig. 1 and 2, the optical film 2 according to the embodiment of the present invention is provided on the light exit side of the backlight 1, and is configured to increase the backlight light exit amount at least at a viewing angle of 20 ° to 60 ° and/or-20 ° to-60 °.

According to actual needs, the backlight light output quantity of the backlight with the positive angle of view angle beta of 20-60 degrees can be improved; the backlight light output quantity of the negative angle field angle alpha between minus 20 degrees and minus 60 degrees can be improved; the backlight light output quantity of the backlight with the positive angle of view beta of 20 degrees to 60 degrees and the negative angle of view alpha of-20 degrees to-60 degrees can be simultaneously improved, and the backlight light output quantity is also shown in figure 3.

Here, the field angle in the direction perpendicular to the optical film or the display surface is 0 °, and the field angle of 0 ° is inclined in the clockwise direction and the counterclockwise direction, and is a corresponding positive field angle β and a negative field angle α, respectively. For example, in fig. 2, the clockwise direction is a positive angle of view β, and the counterclockwise direction is a negative angle of view α. In fig. 2, the collimated light emitted from the backlight 1 is directly emitted through the optical film 2, and then the amount of light emitted is maximized at a position where the viewing angle is about-30 °, and accordingly, the luminance peak is also about-30 °.

In the above scheme, the optical film 2 can at least improve the backlight light output quantity of the field angle of 20 to 60 degrees and/or-20 to-60 degrees, so that the brightness of the field angle of 20 to 60 degrees and/or-20 to-60 degrees can be improved without improving the backlight brightness, that is, the side-view brightness is improved, and the development of products towards low power consumption is facilitated.

As an implementable manner, the optical film 2 includes a substrate layer 21, and a side of the substrate layer 21 facing the backlight 1 is provided with an optical microstructure for changing a light propagation path to a predetermined direction. For example, but not limited to, etching, embossing, etc., optical microstructures are formed on the substrate layer.

For example, but not limited to, the thickness of the substrate layer 21 may be about 50um-200um, and the height of the optical microstructures may be about 10um-50 um.

In an implementation manner, the optical microstructures are stripe-shaped protrusions with triangular or quadrangular cross sections, for example, the stripe-shaped protrusions extend in a direction perpendicular to the view shown in fig. 2. The triangular section can be an isosceles triangle 23, an equilateral triangle, a right-angled triangle 22, an acute triangle, etc. according to actual needs. Generally, when an isosceles triangle or an equilateral triangle is adopted, the brightness within certain field angles β and α of positive and negative angles can be simultaneously improved, and the brightness improvement degrees within the field angles β and α are basically similar; when the right-angled triangle is adopted and one right-angled side of the right-angled triangle is taken as a bottom side to be connected with the base material layer, the brightness within a certain field angle range of a positive angle or a negative angle can be only improved; the brightness of the positive angle and the negative angle within certain angle ranges of view beta and alpha can be improved simultaneously when the acute angle triangle is not consistent with the two acute angles in contact with the substrate layer, and the brightness of the two angles with the same angle absolute value within the angle ranges of view beta and alpha is improved differently, for example, the angle of view beta is 10-50 degrees, the brightness peak value is 30 degrees, the angle of view beta is alpha range from-20 degrees to-60 degrees, the brightness peak value is-40 degrees, and the brightness value is different for the two angles with the same angle absolute value of 30 degrees and-30 degrees, and the specific difference is related to the difference value of the two acute angles.

As shown in fig. 2, the optical microstructure is a stripe-shaped protrusion having a right triangle shape 22 as a cross section, and the cross-sectional shape of the right triangle 22 is adopted, in this example, it improves only the brightness within a certain field angle α of a negative angle, such as a brightness peak around-30 ° at the field angle.

As shown in fig. 5, the optical microstructure is a stripe-shaped protrusion having a cross section of an isosceles triangle 23, and the cross-sectional shape of the isosceles triangle 23 can improve the luminance within a range of certain angles of view β, α, both positive and negative angles, in this example, the peak luminance values are around-30 ° and 30 °.

As a realizable way, when the cross section of the optical microstructure is a quadrangle, the quadrangle is a trapezoid. According to actual needs, the trapezoid can be a right-angle trapezoid, an isosceles trapezoid or a common acute-angle trapezoid, generally, the isosceles trapezoid can be adopted to simultaneously improve the brightness within a certain field angle range of a positive angle and a negative angle, and the brightness improvement degrees within the field angle range of beta and alpha are basically similar; when the right trapezoid is adopted, the brightness in a certain field angle range of a positive angle or a negative angle can be improved, when the common acute trapezoid is adopted, the brightness in the certain field angle range of the positive angle and the negative angle can be improved simultaneously, the brightness improvement degrees of two angles with equal angle absolute values are different in the field angle range of beta and alpha, for example, the field angle beta is 10-50 degrees, the brightness peak value is 30 degrees, the field angle beta is alpha range-20 degrees to-60 degrees, the brightness peak value is-40 degrees, and the brightness value is different for two angles with equal angle absolute values of 30 degrees and-30 degrees, and the specific difference is related to the difference value of the acute angles of the two base angles of the trapezoid. In addition, when the section of the optical microstructure is trapezoidal, the sufficient display brightness of the 0-degree angle of view can be ensured.

As shown in fig. 3 and 4, the optical microstructure is a stripe-shaped protrusion having an isosceles trapezoid cross section, and the isosceles trapezoid cross section can improve the luminance within a range of the predetermined angles of view β and α between the positive and negative angles and ensure sufficient display luminance at the angle of view of 0 °, in this example, the luminance peaks are about 0 °, -30 °, and 30 °.

As shown in fig. 6, the optical microstructure is a stripe-shaped protrusion having a straight trapezoidal cross section, and the straight trapezoidal cross section can improve the luminance in a range of a certain field angle β, α, which is a positive angle or a negative angle, and can secure a sufficient display luminance at a field angle of 0 °, in this example, the luminance peak is about 0 °, -30 °.

In an implementation manner, the lower base of the trapezoid is connected to the substrate layer, the upper base is far away from the substrate layer, and the backlight light output amount at the angle of 0 ° is positively correlated to the length of the upper base, that is, the longer the length of the upper base is, the more the backlight light output amount at the angle of 0 ° is, the higher the corresponding brightness is.

As an implementation manner, in order to prevent the optical film 2 and other film materials in the backlight from generating the problems of poor display such as absorption, water ripple and uneven brightness, at least some of the strip-shaped protrusions have different heights, and the strip-shaped protrusions are set to have different heights, so that the optical film can be prevented from being absorbed on the adjacent structural layer, and the optical microstructures on the optical film and the adjacent structural layer are all in air gaps, so that the light refraction can be uniform, and the problems of poor display such as water ripple and uneven brightness caused by non-uniform degrees of light refraction at different positions of absorption or non-uniformity due to the fact that some optical films are absorbed on the adjacent structural layer and no air gaps exist between the other optical microstructures and the adjacent structural layer are prevented.

As an implementation manner, when the cross sections of two adjacent strip-shaped protrusions are equal, the distance between the vertexes of the two adjacent strip-shaped protrusions is less than or equal to the bottom edge of any one of the two adjacent strip-shaped protrusions; under the condition that the cross sections of two adjacent strip-shaped bulges are similar, the distance between the vertexes of the two adjacent strip-shaped bulges is smaller than or equal to the bottom side with larger size in the two adjacent strip-shaped bulges. Cross-sectional similarity, as used herein, means that the cross-sectional shapes are the same, but are scaled globally in size.

For example, as shown in fig. 7, the optical microstructures disposed on the substrate layer 21 are strip-shaped protrusions with isosceles triangles 23 in cross section, the isosceles triangles 23 are divided into two sizes, i.e., large triangles and small triangles, generally, the number of the small triangles is greater than that of the large triangles, and the distance D1 between the vertexes of two adjacent small triangles is less than or equal to the length D2 of the base of the small triangles. The distance D3 between the vertexes of two adjacent large and small triangles is less than or equal to the length D4 of the base of the large triangle.

For example, as shown in fig. 8, the optical microstructure disposed on the substrate layer 21 is a strip-shaped protrusion with a cross section of a right trapezoid 24, a lower bottom of the right trapezoid 24 is connected to the substrate layer 21, an upper bottom of the right trapezoid 24 is far away from the substrate layer 21, the right trapezoid 24 is divided into two types, i.e., a large right trapezoid and a small right trapezoid, generally, the number of the small right trapezoids is greater than that of the large right trapezoids, and a distance D5 between vertexes of two adjacent small right trapezoids is less than or equal to a length D6 of a base (i.e., a lower bottom) of the small right trapezoid. The distance D7 between the vertexes of two adjacent large and small right-angled trapezoids is less than or equal to the length D8 of the bottom edge (namely the lower bottom edge) of the large right-angled trapezoid. The distance between the vertices here refers to the distance between the vertices on the same side, and as shown in fig. 8, the distance between the left vertices of two small right trapezoids, but may be the distance between the right vertices in other examples.

As a practical mode, the refractive index of the optical microstructure and the refractive index of the substrate layer may be determined according to circumstances, and the refractive index of the optical microstructure may be greater than, equal to, or less than the refractive index of the substrate layer. In the present example, the refractive index of the optical microstructure is greater than that of the substrate layer, and the light propagates from the backlight side to the optical microstructure and then enters the substrate layer to be refracted by a large angle, so that the brightness at a larger viewing angle can be further improved.

In order to prevent crosstalk, the cross-sectional shapes of the optical microstructures provided on the same substrate layer 21 are similar, and the deflection directions of light passing through different optical microstructures are the same. The term "similar cross-sectional shape" as used herein means that the cross-sectional patterns are the same but have different sizes, for example, in fig. 7, similar triangular stripe-shaped projections having different sizes are provided.

In a second aspect, the present invention provides a polarizer, including the optical film 2. The polaroid integrates the functions of polarizing and improving the brightness of a preset field angle, and is favorable for reducing the thickness of a display module adopting the polaroid.

For example, the polarizer includes a polarizing functional layer and the optical film, the polarizing functional layer may be a film made of PVA (polyvinyl acetate) material, and films made of TAC (Triacetyl cellulose) material may be further disposed on upper and lower sides of the polarizing functional layer to support and protect the polarizing functional layer. When the TAC film layers are disposed on the upper and lower sides of the polarizing functional layer, the polarizing functional layer may be directly bonded to the optical film through an OCA (optical Clear Adhesive), a pressure sensitive Adhesive, or the like, and when the TAC film layers are disposed on the upper and lower sides of the polarizing functional layer, the TAC film layers may be bonded to the optical film through an OCA (optical Clear Adhesive), a pressure sensitive Adhesive, or the like.

Of course, in other examples, as shown in fig. 9, other layers may be further included, and specifically, the polarizer includes a release film 201, a first pressure sensitive adhesive layer 202, a first TAC layer 203, a first adhesive layer 204, a PVA layer 205, a second adhesive layer 206, an optical film 2, a third adhesive layer 207, a second TAC layer 208, a fourth adhesive layer 209, and a protective film layer 210, which are sequentially disposed. The optical film 2 includes a substrate layer 21 and stripe-shaped protrusions having isosceles triangle 23 cross-sections. The optical film 2 microstructure is one of the microstructures in the optical film, and the optical film 2 is not limited in sequence position in the polarizer and can be arranged in contact with any one of other layers.

In a third aspect, the present invention provides a display device, including the optical film or the polarizer. The display device provided by the invention is additionally provided with the optical film or the polaroid of the scheme on the basis of the structural design of the existing display device, and the optical film can be arranged between the backlight source of the display device and the light incident side of the liquid crystal box or attached to the surface of the light emergent side of the liquid crystal box. The polarizer is designed to replace any common polarizer in the existing display device, namely, any polarizer in the display device provided by the invention can adopt the polarizer of the scheme of the invention, and other designs can adopt the existing scheme, so that the patent is not limited.

For example, as shown in fig. 10, the important units of the display device include a light guiding or uniformizing layer 301, and a light emitting side film layer 302, the optical film 2, a first polarizer 303, a liquid crystal cell 304, and a second polarizer 305 are sequentially disposed on the light emitting side of the light guiding or uniformizing layer 301. Wherein the light guiding or light homogenizing layer 301 may include a light homogenizing/diffusing plate and/or a light guiding plate, etc.; the light-emitting side film layer 302 may include a lower diffusion sheet, a lower prism sheet, an upper diffusion sheet, etc. in sequence from the light-emitting side to the light-emitting side, wherein the film layers may be combined with each other, which is not limited in this patent.

For another example, as shown in fig. 11, the important units of the display device include a light guiding or uniformizing layer 301, and a light emitting side film layer 302, a first polarizer 303, a liquid crystal cell 304, a second polarizer 305 and the optical film 2 are sequentially disposed on the light emitting side of the light guiding or uniformizing layer 301. Wherein the light guiding or light homogenizing layer 301 may include a light homogenizing/diffusing plate and/or a light guiding plate, etc.; the light-emitting side film layer 302 may include a lower diffusion sheet, a lower prism sheet, an upper diffusion sheet, etc. in sequence from the light-emitting side to the light-emitting side, wherein the film layers may be combined with each other, which is not limited in this patent. The optical film 2 is disposed on the light-emitting side of the second polarizer 305, and may be attached by using OCA, subsensitive adhesive, or the like.

The optical microstructure in the optical film 2 and the polarizer used in the display device is one of all the optical microstructures, and the specific type of the optical microstructure can be determined according to actual needs.

It will be understood that any orientation or positional relationship indicated above with respect to the terms "central," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc., is based on the orientation or positional relationship shown in the drawings and is for convenience in describing and simplifying the invention, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and is therefore not to be considered limiting of the invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may also be oriented 90 degrees or at other orientations and the spatially relative descriptors used herein interpreted accordingly. The connection between the components may be direct or indirect via another component.

The foregoing description is only exemplary of the preferred embodiments of the present application and is provided to illustrate the principles of the technology employed, and that the invention may include more than one embodiment in each implementation. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims

1. An optical film which is provided on the light exit side of a backlight and which is characterized by increasing the amount of light exiting from the backlight at least at a viewing angle of 20 DEG to 60 DEG and/or-20 DEG to-60 deg.

2. The optical film according to claim 1, comprising a substrate layer, wherein an optical microstructure for changing a propagation path of light to a predetermined direction is provided on a side of the substrate layer facing the backlight.

3. The optical film of claim 2, wherein the optical microstructures are stripe-shaped protrusions with triangular or quadrangular cross section.

4. The optical film according to claim 3, wherein when the cross section of the optical microstructure is a quadrangle, the quadrangle is a trapezoid.

5. The optical film according to claim 4, wherein the lower base of the trapezoid is connected to the substrate layer, the upper base is away from the substrate layer, and the backlight light output amount at a 0 ° viewing angle is positively correlated to the length of the upper base.

6. The optical film according to claim 3, 4 or 5, wherein at least some of the stripe-shaped protrusions have different heights.

7. The optical film according to claim 6, wherein, in a case where the cross sections of two adjacent stripe-shaped protrusions are equal, the distance between the apexes of the two adjacent stripe-shaped protrusions is smaller than or equal to the base of any one of the two adjacent stripe-shaped protrusions; under the condition that the cross sections of two adjacent strip-shaped bulges are similar, the distance between the vertexes of the two adjacent strip-shaped bulges is smaller than or equal to the bottom side with larger size in the two adjacent strip-shaped bulges.

8. The optical film according to any one of claims 3 to 5, wherein the cross-sectional shapes of the optical microstructures disposed on the same substrate layer are similar.

9. A polarizer comprising the optical film according to any one of claims 1 to 8.

10. A display device comprising the optical film according to any one of claims 1 to 8 or the polarizer according to claim 9.